1. Field of the Invention
This invention generally relates to a positioning device, and, in particular, to a positioning table assembly for positioning a table at a desired location at high accuracy.
2. Description of the Prior Art
In a typical prior art positioning table assembly, a motor fixedly attached to a table has a shaft coupled to a ball screw so that the table may be moved in a desired direction depending on in which direction the motor is driven to rotate. However, such a structure tends to be bulky and since the motor mounted on the table has a relatively large weight which would tend to hinder an accurate control in positioning operation. Thus, there has been a need to develop a novel positioning table assembly compact in size and high in accuracy.